usbip: tools: add hint when no exported devices are found

When refresh_exported_devices() finds no devices, it's helpful to
inform users about potential causes. This could be due to:

1. The usbip driver module is not loaded.
2. No devices have been exported yet.

Add an informational message to guide users when ndevs == 0.

Also update the condition in usbip_host_driver_open() and
usbip_device_driver_open() to check both ret and ndevs == 0,
and change err() to info().

Message visibility by scenario:
- usbipd (console mode): Show on console/serial, this allows instant
  visibility for debugging.
- usbipd -D (daemon mode): Message logged to syslog, can keep logs for
  later traceability in production. Also can use "journalctl -f" to
  trace on console.

Suggested-by: Shuah Khan <skhan@linuxfoundation.org>
Signed-off-by: Zongmin Zhou <zhouzongmin@kylinos.cn>
Reviewed-by: Shuah Khan <skhan@linuxfoundation.org>
Link: https://patch.msgid.link/20260402083204.53179-1-min_halo@163.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/tools/usb/usbip/libsrc/usbip_device_driver.c b/tools/usb/usbip/libsrc/usbip_device_driver.c
index 927a151fa9aa9e52c5c721f20c34d1682575b17f..1dfbb76ab26c3d43e19953f407498e91a02944f9 100644 (file)
--- a/tools/usb/usbip/libsrc/usbip_device_driver.c
+++ b/tools/usb/usbip/libsrc/usbip_device_driver.c
@@ -137,9 +137,9 @@ static int usbip_device_driver_open(struct usbip_host_driver *hdriver)
        INIT_LIST_HEAD(&hdriver->edev_list);
 
        ret = usbip_generic_driver_open(hdriver);
-       if (ret)
-               err("please load " USBIP_CORE_MOD_NAME ".ko and "
-                   USBIP_DEVICE_DRV_NAME ".ko!");
+       if (ret || hdriver->ndevs == 0)
+               info("please load " USBIP_CORE_MOD_NAME ".ko and "
+                    USBIP_DEVICE_DRV_NAME ".ko");
 
        return ret;
 }

diff --git a/tools/usb/usbip/libsrc/usbip_host_common.c b/tools/usb/usbip/libsrc/usbip_host_common.c
index ca78aa368476207c5a93196ea45da46c649e94f4..01599cb2fa7bd41e7aa1f502deb3b479e3437288 100644 (file)
--- a/tools/usb/usbip/libsrc/usbip_host_common.c
+++ b/tools/usb/usbip/libsrc/usbip_host_common.c
@@ -149,6 +149,9 @@ static int refresh_exported_devices(struct usbip_host_driver *hdriver)
                }
        }
 
+       if (hdriver->ndevs == 0)
+               info("Please load appropriate modules or export devices.");
+
        return 0;
 }
 

diff --git a/tools/usb/usbip/libsrc/usbip_host_driver.c b/tools/usb/usbip/libsrc/usbip_host_driver.c
index 573e73ec36bd3fb6c555e48fa499277a47f640b6..bd8a6b84de0ec8b8f30a678c1b8404bb87d23a85 100644 (file)
--- a/tools/usb/usbip/libsrc/usbip_host_driver.c
+++ b/tools/usb/usbip/libsrc/usbip_host_driver.c
@@ -32,9 +32,10 @@ static int usbip_host_driver_open(struct usbip_host_driver *hdriver)
        INIT_LIST_HEAD(&hdriver->edev_list);
 
        ret = usbip_generic_driver_open(hdriver);
-       if (ret)
-               err("please load " USBIP_CORE_MOD_NAME ".ko and "
-                   USBIP_HOST_DRV_NAME ".ko!");
+       if (ret || hdriver->ndevs == 0)
+               info("please load " USBIP_CORE_MOD_NAME ".ko and "
+                    USBIP_HOST_DRV_NAME ".ko");
+
        return ret;
 }